By Dona Suri
Vitamin C is also called ascorbic acid and ascorbate.
It is a water-soluble vitamin. Toxicity is rare in comparison to fat-soluble vitamins.
An antioxidant; it aids in defending the body against effects of toxins, pollutants, and free radicals.
The body can’t make vitamin C on its own and does not store it. Sufficient Vitamin C must be consumed every day.
How the body gets Vitamin C
* When Vitamin C, whether in food or in supplements, enters the small intestine, it is taken up by two types of proteins:
Sodium-ascorbate co-transporters (SVCTs)
Hexose transporters (GLUTs)
* When vitamin C is present at low concentrations, the majority of it is digested in the small intestinal epithelium.
* When vitamin C is present in high concentrations, the body uses the SVCTs to restrict excess uptake. The excess is excreted through the kidneys.
* The bioavailability of ascorbic acid is essentially dependent on how well it is absorbed from the gut and how much of it is excreted by the kidneys.
The body uses Vitamin C in . . .
The body processes Vitamin C into long-acting ascorbic acid 2-phosphate, a long-acting ascorbic acid derivative. These molecules increase cell proliferation and mRNA for type 3 collagen in two kinds of cells:
Osteoblasts (cells that grow and heal bones)
Mesenchymal stem cells (cells in bone marrow that can differentiate into many cell types.)
Collagen
If the body doesn’t get enough Vitamin C then it struggles to make collagen, which is the body’s main protein. Collagen is the tissue in skin, bone, cartilage, blood vessels, intervertebral discs, corneas, and eye lenses. Wounds heal because the body repairs the damage with new collagen.
Bone and bone marrow
The body processes Vitamin C into long-acting ascorbic acid 2-phosphate, a long-acting ascorbic acid derivative. These molecules increase cell proliferation and mRNA for type 3 collagen in two kinds of cells:
* Osteoblasts (cells that grow and heal bones)
* Mesenchymal stem cells (cells in bone marrow that can differentiate into many cell types.)
Neurological processes
Vitamin C protects neurons from oxidative stress, induces differentiation and maturation of neurons, and regulates the synthesis or release of neuro-modulating factors including serotonin, catecholamines, and glutamate. Vitamin C helps convert dopamine into another neurotransmitter, norepinephrine. When norepinephrine levels are low, it leads to depression or anxiety.
Regulation of hormones
Vitamin C regulates cortisol and adrenaline levels, stabilises testosterone levels, improves sperm quality and motility, raises progesterone levels. (Sufficient progesterone helps women to conceive and carry a fetus to term. After an ovary releases an egg, progesterone levels should rise, leading to increase in the thickness of the uterine lining. A fertilized egg will not implant, or remain implanted, if the lining of the uterus is too thin.)
Regulation of cholesterol
It modulates the way cholesterol is broken down or accumulated in the liver.
Cholesterol: HDL is “good”, LDL is “bad”. While Vitamin C does not increase HDL-cholesterol, it does lower LDL cholesterol and triglyceride. It does this by increasing the ability of the liver to transform cholesterol into bile acids
Regulation of iron in the body
Vitamin C enables the body to absorb iron from food. The body needs iron in order to make haemoglobin and myoglobin.
Hemoglobin is the protein in red blood cells; it carries oxygen from the lungs to all parts of the body.
Myoglobin takes oxygen from haemoglobin and transfers it to the muscles.
People who haven’t enough iron in their blood are anemic.
Vitamin C helps to maintain a correct level of hepcidin in the body. Hepcidin is a hormone that regulates how much iron is available for essential body functions. It stimulates when iron is needed and inhibits absorption of iron when the body already has enouugh. Vitamin C prevents overproduction of hepcidin, thus protecting against anaemia.
The immune system
Vitamin C ramps up immune response by:
Increasing T-lymphocyte proliferation. (T-lymphocytes destroy the infected targets)
Assisting B cells in the synthesis of immunoglobulin to regulate inflammatory responses
Blocking pathways that cause T-cell apoptosis
Can Vitamin C ward off or cure a cold? Yes and No.
Clinical trials with various doses of Vitamin C have found that it does not cure a cold, but it does reduce the intensity and duration of symptoms during the infection period. You will get over a cold faster with Vitamin C than without it.
How much Vitamin C is enough?
Here’s a chart with the recommended intake.
If you take more Vitamin C than your body needs, then the body will simply excrete it. It does not store Vitamin C. Remember, for most people, a healthy diet provides enough vitamin C.
Large doses of vitamin C supplementation are not recommended during pregnancy. They can lead to shortage of vitamin C in the baby after delivery.
Although too much dietary vitamin C is unlikely to be harmful, large doses of vitamin C supplements (greater than 2,000 mg/day) might cause: diarrhea, nausea, vomiting, stomach cramps, headache, heartburn, kidney stones.
